[R] file.access returning -1 for a file on remote Windows drive.

Jeff Newmiller jdnewm|| @end|ng |rom dcn@d@v|@@c@@u@
Sat Feb 29 00:40:06 CET 2020


Read the closed issues in his digest Github repo first... this discussion has already occurred there.

On February 28, 2020 3:35:09 PM PST, Sam Albers <tonightsthenight using gmail.com> wrote:
>Great question Will. If it were my code I would definitely do this.
>However the problem is manifesting itself for my work with Dirk's
>great digest package here:
>
>https://github.com/eddelbuettel/digest/blob/947b77e82b97024a874a808a4644be21fc329275/R/digest.R#L170-L173
>
>So because file.access is saying the permissions aren't right, I get
>an error message from digest and can't create a hash. Knowing full
>well that this is some weird Windows thing but also knowing I am stuck
>in that environment, I wanted to figure where I was seeing a
>difference between those two functions before I went asked Dirk if
>he'd be interested in a change to that particular bit of code.
>
>
>On Fri, Feb 28, 2020 at 3:28 PM William Dunlap <wdunlap using tibco.com>
>wrote:
>>
>> If file.access() says the file is unreadable but file() says it can
>be opened, why don't you
>> just open the file and read it?  You can use tryCatch to deal with
>problems opening or
>> reading the file.
>>
>> Bill Dunlap
>> TIBCO Software
>> wdunlap tibco.com
>>
>>
>> On Fri, Feb 28, 2020 at 2:54 PM Sam Albers
><tonightsthenight using gmail.com> wrote:
>>>
>>> Thanks Jeff. I am probably not explaining myself very well but my
>>> question under what circumstances would
>>>
>>> summary(file(remote_file, "rb"))$`can read`
>>>
>>> be different from:
>>>
>>> file.access(remote_file, 4)
>>>
>>> If my permissions were different across remote and local should that
>>> not be reflected in both of these functions?
>>>
>>> On Fri, Feb 28, 2020 at 2:37 PM Jeff Newmiller
><jdnewmil using dcn.davis.ca.us> wrote:
>>> >
>>> > Dunno. They agree for me. Maybe look closer at all permissions via
>Windows File Manager?
>>> >
>>> > On February 28, 2020 2:06:34 PM PST, Sam Albers
><tonightsthenight using gmail.com> wrote:
>>> > >Some additional follow-up:
>>> > >
>>> > >> summary(file(remote_file, "rb"))$`can read`
>>> > >[1] "yes"
>>> > >
>>> > >> summary(file(local_file, "rb"))$`can read`
>>> > >[1] "yes"
>>> > >
>>> > >compared to:
>>> > >
>>> > >> file.access(local_file, 4)
>>> > >local.R
>>> > >         0
>>> > >
>>> > >> file.access(remote_file, 4)
>>> > >remote.R
>>> > >            -1
>>> > >
>>> > >Can anyone think why file.access and file would be contradicting
>each
>>> > >other?
>>> > >
>>> > >Sam
>>> > >
>>> > >On Fri, Feb 28, 2020 at 10:47 AM Sam Albers
>>> > ><tonightsthenight using gmail.com> wrote:
>>> > >>
>>> > >> Hi there,
>>> > >>
>>> > >> Looking for some help in diagnosing or developing a work around
>to a
>>> > >> problem I am having on a Windows machine. I am running R 3.6.2.
>>> > >>
>>> > >> I have two identical files, one stored locally and the other
>stored
>>> > >on
>>> > >> a network drive.
>>> > >>
>>> > >> For access:
>>> > >>
>>> > >> > file.access(local_file, 4)
>>> > >> local.R
>>> > >>          0
>>> > >>
>>> > >> > file.access(remote_file, 4)
>>> > >> remote.R
>>> > >>             -1
>>> > >>
>>> > >> Also for file.info
>>> > >>
>>> > >> > file.info(local_file)$mode:
>>> > >> [1] "666"
>>> > >>
>>> > >> > file.info(remote_file)$mode:
>>> > >> [1] "666"
>>> > >>
>>> > >> Ok so I am access issues. Maybe they are ephemeral and I can
>change
>>> > >> the permissions:
>>> > >>
>>> > >> > Sys.chmod('remote.R', mode = '666')
>>> > >> > file.access(remote_file, 4)
>>> > >> remote.R
>>> > >>             -1
>>> > >>
>>> > >> Nope. I am thoroughly stumped and maybe can't make it any
>further
>>> > >> because of Windows.
>>> > >>
>>> > >> Downstream I am trying to use digest::digest to create a hash
>but
>>> > >> digest thinks we don't have permission because file.access is
>>> > >failing.
>>> > >> Any thoughts on how I can get file.access to return 0 for the
>>> > >remote.R
>>> > >> file? Any ideas?
>>> > >>
>>> > >> Thanks in advance,
>>> > >>
>>> > >> Sam
>>> > >
>>> > >______________________________________________
>>> > >R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> > >https://stat.ethz.ch/mailman/listinfo/r-help
>>> > >PLEASE do read the posting guide
>>> > >http://www.R-project.org/posting-guide.html
>>> > >and provide commented, minimal, self-contained, reproducible
>code.
>>> >
>>> > --
>>> > Sent from my phone. Please excuse my brevity.
>>>
>>> ______________________________________________
>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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>>> PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.

-- 
Sent from my phone. Please excuse my brevity.



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